LEDs are current-dependent elements and in LED lighting system, LED driver control systems control this current. More specifically, an LED driver control system is connected between a power source (e.g., an AC power supply) and the LEDs for controlling the current supplied to the LEDs.
Some LED driver configurations employ pulse width modulation (PWM) to switch the output on and off which controls the output current to the LEDs. In these configurations, PWM provides control for alternating the brightness of the light output from the LEDs. PWM dimming is typically controlled by current via supply of a pulsed signal with a varying duty cycle to the LEDs.
Deep dimming of LEDs within a lighting system is becoming an increasingly preferred effect. The deep dimming process involves dimming the LEDs to approximately a 1% output current level without having any visible flickering of the LEDs. In current lighting systems, as the level of dimming decreases, other components of the LED driver enter a burst mode operation which results in undesirable visible flickering in the LEDs of the lighting system.